If players are attached to their favorite islands, make them fight for them.
I say bring the BT-style Invasions everywhere (I would be happy to volunteer for GM duty). Make them difficult, but beatable, like the Fifth Invasion was. If a particular island can't cut it, it will lose all or most of its regions. Even the strong islands may suffer from region losses like BT did. Islands with low player densities will theoretically prove to be more vulnerable to this, as is only fitting.
If players at least have the opportunity to save their favorite islands, they will feel better about what ultimately ends up happening to them, and even if they fail the process will provide closure. The story will have an end.
I would suggest merging continents first by attaching them through sea routes and then have the Blight come in and sink some land so the amount of land overall could stay almost the same. The only problem is that the map would get huge and take forever to cross so we could make the Earth round! Have the east side of continent A link to the west side of continent B and east side of continent B link to west side of continent A
I like both suggestions. Both seems to be a good way to make one continent disappear although Sacha's idea for a reset sounds good too.
To make we fight for our continent would show wich continent have more active players I think.
Another suggestion, that I don't know if its possible, is to simply pause one continent. Make it sleep, get invaded by undeads and monsters due to a magic. Stop the bleeding and find new ways to increase players base and than, re-open it.
This can also be the result of the continent that cannot defend appropriately.
